Party-line telephone system.



W. T. POWELL. PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED APR. 21. 19H5. 1,26'7,1 13,

Patented May 2T, 1918.

W. T. POWfLL.

PARTY UNE TELEPHONE SYSTEM.

APPHCATHM FILF WR-27. IQIE.

Patented May 2l, l9l8.

ilulx IULI UNITED STATES PATENT OFFICE.

WINFRED T. POWELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PARTY-LINE TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented May 21, 1918.

Application filed April 27, 1916. Serial N o. 94,019.

T o all whom it may concern:

Be it known that I` WINFRED T. PownLL, a citizen of the United States of America,

and resident of Chicago, Cook county, 111i-- nois, have invented certain new and useful Improvements in Party-Line Telephone Systems, of which the following is a spec1- fication.

Thisyinvention relates to party-line telephone exchange systems in general, but is concerned more particularly with the socalled automatic party-line telephone systems, in which connections are established through the medium of subscriber controlled switches.

In telephone systems of the above char acter, when one or more stations on a line has been disconnected it becomes necessary to provide an arrangement whereby when a calling telephone station attempts to com` plete a connection with the disconnected station, the call will be received by an operator who will proceed to inform the calling station that the called station is no longer accessible.

The principal object of this invention is the provision of an improved, simple and inexpensive arrangement whereby when any station on a party-line has been disconnected or taken out and the said station is called by a subscriber at another station, the call will be switched to a so-called traffic trunk extending to an operators position.

It is also an object to provide certain de tails and features of improvement tending to increase the general eiiiciency and serviceabilty of a telephone exchange system of this particular character.

To the foregoing and other useful ends this invention consists in matters hereinafter set forth and claimed.

Figures-1 and 2, of the accompanying drawings, taken together represent diagrammatically a complete circuit connection betweern a calling substation A (Fig. l) and au operators equipment 0 (Fig. 2), it beingl assumed that substation A attempted to secure connection with substation F (Fig. 2), which for the purposes of this explanation is assumed to have been taken out or disconnected from the line.

Fig. l illustrates diagrammatically a substation telephone A, which is connected, at the central oflice. to un individual or line switch C. A group of line switches, such as C, is controlled by the common mechanism or master switch D. At H is represented a connector switch with which is associated a. frequency selecting switch S. The said frequency selectin switch is operable to elect one of a plura ity of ringing current generators, such as It', R2, R31 and R", and their associated relay equipments. At J is shown a ringer relay interrupter Which is common to the ringer relay equipments and is adapted to control the intermittent application of ringing current to called telephone lines. A battery B having one ter` minal grounded is provided for the purpose of supplying current for operating the central oflice equipment and for talking purposes. A busy machine M .is shown associated with the connector H and is provided for the purpose of supplying a busy tone to the calling station should the connector attempt to complete connect-ion with a busy line. f

In Fig. 2 there is illustrated my improved relay equipment which is shown connected in the proper manner to switch calls intended for the discontinued station F to the traffic trunk 152-153- line switch which is similar to the one shown at C. The line switch E serves the partyline having the subscribers stations G, H, and I, and the subscribers station F, which has been temporarily disconnected.

Fig. 3 illustrates a portion of the connector switch having particular reference to the method of releasing the frequency selecting device associated with the connector.

- Figs. 4, 5 6, and 7 illust-rate the various circuit arrangements which are to be used in the event one of the other stations 0n the line is disconnected or otherwise rendered inaccessible to calling subscribers, the substation I4-` being `retained in service.' These arrangements will be hereinafter more fully explained.

The substations may be of any suitable or approved type. Those with which- I have elected to illustrate this invention are all alike. Substation A comprises a receiver 2, switch-hook' 3, transmitter 4, ringer 5, condenser 6, impulse wheel 7, and impulse springs 8 and 9. The switch-hook, when relieved of the receiver, rises to open the ringer circuit and connects the receiver and transmitter across the line. The impulse wheel 7 is provided with a finger hold dial At E is shown a (not shown) which is rotated to transmit the required number of impulses. The talling device comprising the wheel l und its associated impulse trz'insniittingr inecluinisln may be of the type of culling,r device shown in U. S. Letters Potent to Il'. G. Blessing, No. 1,119,394, grunted December 1, 191i.

The ringcrs shown associated with the sta'- tions F, (fi, ll und l, of the party line, ure of the well known harmonic type-that in, they ure euch adapted to be operated by 1"ui f'in, y current of n. certain frequency und not by .-nrx'cntof other frequencies. The ringer oft' euch telephone on any particular lintl inlnptcfl lobe operated by :i ditl'ercnt frequentr of ringing current.

The liuc switch C is of the general type of line switch disislosed in British intent to R. Vl'. deines. No. 26,301 of 1906, eilig, howereigvof the particular type shown in U. Letter-,s- Patent to F. Newforth, Jr., No. 55.001, raies-neil 'April 13, 1915.

r-ince line switches of the. foregoing type nrc well linou'n. itfwill he. unnecessary to giwun extended description here. lt. will. sutltse to sin; that through the medium of line snitchf', the line ol' substation A, when culling. giron neces to n plurality of con Hector swim-hr. one of which is shown ut. lfl..

Although in this illustration 1 show the line switch C as having direct eccez-.is to the connector switch l-l, l do not wish to limit myself to the specific arrangement. disclosed herein. Selector switches of any suitable type may be placed between the saidline switch and connector in order to increnne thc capacity of the exch-ringe, without depart ing frein the spirit of my invention.

The master switch D is similar to' the inuster switch shown in British patent lo '.l. Gr. Martin, No. 1419 of 1910.` is well known., the function of the master switch is to mainN tuin tlufplungers of all the idle line switches op iosite the terminali; ot idle trunk linee.'

'he connector ll is ot the'genei-n'l type of connector switch dieclosod in United States Letters Patent No. Stall/Til, grammi liliirch 1.3, 1906, bo Keith, Erickson and Erickson;

being modified, however, to enabie it to operatfejn :i syuteni in which thc operating inipulses tre tl'linsmitted ort-.r two sides of the line' in series, shown in speciliczttion, No. 2270 oi" lill-l, und being pio vided, furthermore. with means tor selectingl i different ringing generators.

A. connector switch of' the foregoing elctracter may be given access to n single group of subscribers lines und 1,: operable in ie eponse to digits of n culled number to extend connection to any `one olI the lint-fs of the group with which it is associated. Since the. general construction of such connectors is well knowmhavingr been fully describetfl in the publications referred to, no extended de tfin of the construction or operacion British patient will be given at this time, Such explanation as is deemed necessary being reserved for the detailed specification.

Since the connector H is adapted for party line service it is provided with a frequency seltuztm' S for Selective ringing purposes. The frequency selector S may be considered us being a [mrt of the connector switch; und ie operable, after the connector has been operntrrd to connectiwith the wanted line, in rcnponfie to the final digit of the wanted nunlhcr to select the proper frequency oi ringing current for signaling the wanted s illmt-.iiion For this purpose the, switch S is provided with plurality of sets of contacts adopted to be traversed by the wipers 28, 29, und 30, each set being the terminal of a set of conductors extending to the :so-called group ringing relays. For example, the firstset of contacts, upon which the wipers are resting, li's the tern'iinel of :i set of conductors extending to relays 56, 57, 58, and oil, which relays are provided for the pur pose of controlling the intermittent application of ringing; current from generator lt to celled lince. Euch of' the remaining sets of mnl'ucts is nssociatcd with n similar group of relays which in turn are associated, re spectvely. with ringingP current` generators "t2, it, and Ht. These generators deliver ringing currents of different frequency. The interruptcr J is common to the different sets of group ringing intermittent impulses for their operation, as will appear more clearly hereinafteri To retin-i to the frequency selector switch S, the wipers 28, 29, und 30 are mounted upon e. ratchet wheel 31, which is adapted to be ro tri-ted step by step by the magnet 32 through the medium of its armature 33 and pewl 34. The pani 35 is provided to prevent backward rotation of the ratchet Wheel durin suocessive impulses und serves to retain the wipers; in the position to which they have been advanced. springs 6i und $2 are closed at the first, operaition o muguet The wipers are released upon the retener of the connector H as may he clearly seen by reference bo Fig.,3. The retaining pawl is provided witll 'n extension '201. Upon the 'energization f release magnet (i0 o connect/or H, the release Yarmature 200 is attracted to effect the disconnection of the connector in the well known manner, und in. so doingl the armature :200 engages the extension arm 201, whereby pnwl. is dieengaged from ratchet wheel 31 and the hitter is returned to normal by a coiled spring (not shown).

Une of the lines to which the connector H` has access is shown extending by Way conductors 101 and 102, contact springs of relay 53 `(Fig. 2), land line conductors 103 und 104, to the party line subst-.ations G, H,

und I, which have been previously men` relays and furnishes the The olf-normal contutr 1i ner in which it, is connected for use tioned. The extension of line Conductors 103 und 10i to substation F is shown dotted to indio-.ite that this substation has been. disconnected. An individual line switch, indicated by reference elizirueter E, is allotted :it the exchange to the. line conductors 108 und 104: of the party line, and like line switch C (Fig. .171) is operable by :t willing substation, ria its i ssocinterl line to ext end connection to :in idlo eeleetor switch.

The relay equipment shonn just. to the left of lino sn'iteli E in Fig. 2 ooiuprisers the principii! part of my invention and the nimh muy be lirieliy described :is follows: ,All partiv lines which :ire filled up to their full eitpfeity have their nornnll conductors eonl'nrered direet to the line` switch bunk springs ,shown in the British Patent: No. 12270 of 1911i, previously referred to. lVhenover :t substation on n certain line is taken out' or disconnected und it is desired to provide tratiie trunk Service for snel] line, the normal conductors are opened :it suitable terminals provided for this purpose und are connected with a. relay equipment. which operates when the diseonnet'tiul substation on the lino iS called to connect the nor-nml conductors with u. trunk extending to un operators position. These relay equipments are provided in stiflioient number 'to take eure of all the lines requiring the traffic trunk serriee, there heing n separate relay equipment needed for euch such line. However, the nuniher of lines which nro considered to require trutlie trunk service is usually sufh n. snnill proportion of the total number of lines that the expense is ineonsidernble.

The individual relaiv equipment shown in. Fig. 2 comprises the relays 52. 525. und lelity .32.` when energizerrl, eounerts` the nounnil oomluetors` lttl :ind 10Q 'with the trellis trunk ll-l. while relay 33, when energized, erinnert these nornnii conductors with the line. Whether relay 5:3. is energized or not when the line is culled depends upon ulnrh group oit ringii'ig return hals been soleils-ld by the tirnqlufney solei-tor of the Culliugf voniieetn und upon the eoiniefftious of l'lie ternnnu u AQ YS.. tl', und D', :is Twill lio fully desrrihed und explnined hereinafter. lieluy .i'li is opernted when the :issoeizited lino is milling tn extend ground tl to the eine nertor iuirnte lisinli rontuits viii rundum! fili in :in riliriiwus inunnfr.

For the purposes of thi. explinnltion it will be assumed tlinl the sntistariber nti suh- Station A t'lfig. l) mille; the number ot the diseonnerftid -ulisfnlirin it (Fig, l, und the manner in ubiifh the vonnel'tinn is nuten-uni will)r swim-lied to the trntiir lrunh through the inediuin ot' the relu) equipment 'will be desifribed in :li-mil. .\l'te|'\\:|rd, other winni-tintin ot' the ielnv euuiiunent, illu-muted in Figs. fi, 5, t3 und T :nid nitide eet-tuin Titi. winding li.

use of when substntions other than substation F ure disonnected, will be briefly exylained.

Referring now to Fig. l, the subscriber at substation A, upon removing his receiver to initiate the call, eloses an energizing circuit'. for the line relay 11. of the line switch C as follows: ground :it G, springs 65, lino condnetor 6G, substation A. line conductor 67, springs 68 and the line relay 11 to the buttery B. The line relay1 upon energizing, closes a. circuit for pull-in winding 12 over the vfollowing path: ground at G2, springs n und master switch controlled contacts T0 to the batteryY B. The winding ii?, upon energizing. attract-s both the ent-ofi' urn. 14' and the plunger-arm l5; the former disconnecting the line conductors 67 and 66 from the Winding of line relay 1l and from ground at G', and the latter, through the medium of its plunger, causing bank springs i6, 17, 18, and 1.9 to engage contacts 20, 2l, 22, and 23, respm'tively. By the engage-I ment of springs 16 und 19 with contacts 20 und 2S, respectively, the line conductors 66 :ind ('7 ere extended to the line relays 26 ind 2i' of the connector ll. An energizing eirenit is thereby closed through line relays .26 :ind 27 :is follows: ground G, relay 27, oonilnetor 7l, Contact circuit previously traced to und through. substation A, .spring 1G1 Contact 20, 'Confluetor F2 and the` relayv E26 to the buttery B. Relays Q6 and Qi' both energize over the :iiore traced circuit whereupon a circuit is closed for release relur 3G, which, upon energizing. establishes n holding eirruit from ground (125 through springs 78, Contact 21, and spring i7 to n point T4, Whore the eireuit divides. one lirnneh extending through the holding winding lil to the buttery B and the other brflneh extending over eonduct'or T5 to the private hnnli contacts of all oonneftor snitrhes wliii'h have uecess to the line of stution ik. The enereirf' g eireuit for redonne relay fill extends from ground (i5 through springs Tft to spring 77 Where it; meets ground G tlnoughpring 78: the eirruit then lends through springs T9 of relay tiind the winding ot relis); 3G to the: butter)r B. The ground lroin ft2 extended to the holding winding i before the line relay' 'll deinergizes tu remore ground (i2 from inellin winding l2. ilu line relui' li being alim' uiting. The ground potential #long running-ten' T to the nimte eontuet's pre` rents :infr other line troni obtaining n eonuni-tion with the culling elution while the reieiwr is removed. B r the engouement' of @tiring 1H with eontmrt :3:2 upon the operai.- tiou of lin@ switch C i eirruit is eouipleted to oiwrnte the muster su'itrli il whereby the pluugers of tinl renniiuing: line switches :ire :now-d to position llel'orcthey terminals ol the next idle truuk.

23i und spring `I9, the 95 l It) battery B.

n.ine operation of the substation ,calling device or the first digit of the number of station F will canse the impulse springs S and 9 to be momentarily separated a number of times corresponding to the numeral of said first digit. If the iirst digit is 2 the impulso springs will be momentarily sepa rated twice to thereby canse line relays 26 and El? to be momentarily dinergized twice. Each time the relay 26 denergizes it closes a circuit for the vertical magnet 40. This circuit extends from ground Gia through springs 78 and 80, springs 81 and 82, slow aotinv relay 37, vertical magnet 40, sidelswiteli wiper (in {irst position) to the The vertical magnet receives two impulses over the above circuit and operates to raise the switch shaft and wipers 42, 43, and 4 4. two steps to a position opposite the second level or of bank contacts. The slow acting private control relay 37 is energized by the first impulse of current which passes through it and remains energized during the suceeeding: impulses. ln its operated position, besides closing the oil-enit of the private magnet 38. the relay 37 short-circuits the relay 27 by the closure of springs 83 and 84. This` short-cirouiting is for the purpose of decreasing the resistance oi' the line circuit while line relay 26 is operating. The denergization of the private control relay 37, after all the impulses have been delivered llo the vertical magnet, breaks the circuit of the private magnet 3S, which operates lo rause the side switch to pass from iirst to second position. The passage of side switch Wiper lj from lirst to second position shifts the battery connection from the vertical magnet to the rotary magnet 41.

The callingr device at substation A may now be operated in accordance with the seo-- ond digit ot the called number, resulting as before in denergizaiions of line relay At each denergization a circuit is Closed through the rotary magnet 41, which circuit extends follows: ground G, springs 58 and B0, springs 8l and 82, relay 37, sl'nings of relay 39, rotary magnet 4l and side switch Wiper l5 to the battery BL The rotary magnet receives two impulses over this circuit and operates to advance the wipers 42, 43 and 44 to the connector bank rontacts of the called party line. The privato control relay 37 operates in the saine manner as for the previous digit to close the circuit ol' the private magnet'SS as long as impulses are being delivered lo he roarj; magnet. After the last impulse is ,leiivered the relay 37 denergizes and opens the virenit of the private magnet 38. If the called line is idle the private magnet there` upon denergizes to permit the side switch to pass to third position. l? the walled line is busy, however, the side switch remains in second position and the caliing substation is given the busy signal in the following manner: l'Vhenever n lino is busy there is a guarding ground potential established at the connector private bank contacts of that. line, as explained in the rase oi: line switch (l, with the ditl'erenvo, howl-yen that in the rase of u party line the :ground potential is applied to the uonnortor bank non# its of." means of a relay similar to relay Consequently, when tine primair wiper 44 is rotated onto the courants oi a busy lino he ground potential is extended from tile guarded private bank eontar through the side switch Wiper il) (in .seoond pijasitioni springs 86 and 8T, and winding oi relai' in? to the spring 88 of private conrol relay ETI ll'hon the relay 3i' denergiaos, ille spring SS) engages spring S8 before it disengagos spring Thus the private magnet is included in the ev-ironi trained to spring The private nnignet remains energized by the ground extending from the priale imnh Contact of the busy .line through the rolav 39, and at the saine time the said relay also becomes energized over the same cir cuit. The relay 39, upon energizing, shifts the spring' Si' into engagement with Zlio spring 90, whereby the holding ground of the relay 39 and private magnet 38 is transfrred .from the private bank Contact to ground G25. The private magnet 3S being energized, a circuit for the inns): tone lo ine Calling iine is thereby igtompleivd ehrouggh springs 9L from the busy machine M. "'lln calling line` wil reoeive the busy (one mail ilu receiver is restored to the switch imola 1when thi,` (.enilai oliiee apparatus will he released in a manner to be explained. ll'lion the relay Bil is energized the springs no are separated so that fordern" rotation of the connector is impossible.

li". hinvefi-r, the called line is not in use and therefore idleA` when the private rontrol relay 37 denergizee after trie wi have been rotated onto the romanes ol an idle line, the. circuit of the private magnet is broken. The private nnlgne', upon deenergiziw', allows ille side swil'oii to pass from second to third position- The sido switch wipers lcl and it! {in third position) extend the line through The shaft wipers .42 and lil to he normal mundillo-tors oi" the. called pan-ty line. The side switch Wiper 4o (in third position) provides an energiaing circuit for relay 53 (Fig. This oircnit extends from `ground Gf' through side switch wiper 45, private 'wiper 4, private bank conaet conductor $3, springs $4 and 05, and the relay 53 to the battery B. branch of this eirenit extends from tinepri 'ate contant 9:? to multiples thereof in the banks of all fonnernor switches Whirl; ma)1 have oerasion to :tall the same party line The relay 53, upon energizing, closes ill) a circuit from ground G8 through springs 96 and 97, conductor 98 and the cutotl winding 54 to the battery B, whereby the cutotl armature is operated to disconnect the line conductors 103 and 104 from their connection in line switch E. By the closure of springs 99 and springs 100 the connector normals 101 and 102 are connected to the line conductors 103 and 104, respectively. The engagement of the side switch wiper with its third position contact point connects the operating magnet 32 of the frequency selecting mechanism with the battery B, thus placing the magnet 32 in condition to he operated in accordance with thi` last digit et' the called number.

The operation of the substation calling device for the final digit, assumed to be in this case the digit 1. results in one denergization of the line relay 26, which transmits an impulse of current 1from ground l through springs 78 and 80, springs 81 and 82, relay 37, operating magnet 32 and the. side switch wiper 45 to the battery B. The magnet receives one impulse over this circuit and operates to advance the Wipers 28, 29, and 30 one step to select the group of relays 56-59 which control the application of current from the ringing current generator R. As soon as the relay 37 denergizes after the last` digit has been transmitted, a circuit is closed through the ringer relay 25 and group relay 56 which extends from ground G9 through high resistanee relay 56, conductor 106, frequency switch wiper 28, springs 107 of relay 24,- ringing relay 25, springs 108 of relay 37, olf-norma] springs 61 and 62. side switch wiper 45 (in third position) to the battery B. The relay 56 is of high resistance and will not permit enough current flow to operatively energize ringer relay 25.

-Relay 56, however, energizes and closes a circuit from ground G10 through interrupter Wiper 109, left hand winding of relay 110, spring 111 and armature 112 to the battery B. Relay 110 energizes and locks from ground G11 through its armature 113. At the same time its armature 114 is brought into Contact with spring 115 Wherebya circuit is closed from ground G10 through a solenoid magnet comprising windings 116 and 117, spring 115, armature 1,14, spring 111, armature 112 to the battery B. The windings 116 and 117,1ipon energizing, attract tll'e plunger arm'1118 carrying the wiper 16a. The wiper lul) connects contacts on its left` with those on its right, but no circuits are closed until the said wiper 109 reaches the limit of its travel when a circuit is closed from ground G1 through Contact 119. wiper 109, Contact 120, right-hand winding of relay 110, spring 115, armature 114, spring 111 and armature 112 to the battery B. The right-hand Winding of relay 110 upon energizing, opposes the left-hand winding and causes said relay 110 to release its armatures. Armature 113 rcngages its back contact, thereby supplying ground from G11 over conductor 121 to the contacts shown together. Armature 114, upon restoring, opens the. circuit of the windings 116 and 117. The windings 116 and 117, upon denergizing, release the plunger arm 118i which proceeds to fall slowly due to the action of dash-pot 122. Then the wiper 109 is carried over the contaets during the restoring movement, it successively closes circuits along conductors 123, 124, 125 and 126, each circuit leading to a different group of relays. Consider the circuit which extends into the grou of relays associated with generator R. This circuit will be closed when the wiper 109 is on the contact 127 and 128, and extends from ground G11 through armature 113 and its back contact, conductor 121, contact 12T, wiper 109, Contact 128, conductor 126, and slow relay 58 in multiple with relay 59 to the battery B. Relays 58 and 59 energize over this circuit. Relay 58 upon energizing, prepares :3. circuit from ground G12 through spring 138 and armature 129 to spring 130. A circuit is also closed from ground G13 through armature 131, spring 132 and the relay 57 to the battery B. Relay 57 upon energiz'ing short circuits high resistance relay 56 from ground G1* thereby permitting ringing relay 25 of the connector to operatively energize. Vilhen relay 59 energized it 'connected its armatures to the leads trom generator R so that generator current will flow from the generator R over hoth generator leads through armatures 132 and 121:1 in Contact With their respective front` springs, through wipers 30 and 29, springs 134 and 135 in Contact with springs 136 and 137, respectively, thence over side switch wipers 48 and 49, line Wipers 42 and 43, and normals 101 and 102 to the lines 103 and 104. However, this generator currentis without any particular function for the reason that substation F whose ringer is adapted to respond to current from generator R', is disconnected from the line.

As soon as wiper 109 breaks away from contacts 12T and 128 the circuit of relays 58 and. 59 is broken and these relays delinergize. Relay 58 being slow acting will retain its armatures for a short time after relay 59 has released its armatures. Therefore, before relay 58 releases its armatures and after relay 59 has allowed its armatures to restore, a circuit is closed from ground G12 through spring 138,armature 129,spring 130, armature 132, conductor 139, frequency switch Wiper 30, conductor 140, springs 134 and 136, side switch wiper 48, line wiper 42, normal conductor 101, springs 141 and 142 of relay 52, middle Winding of relay 52, terminal B,

terminal C', armature 143, and sllring 14%. of relay. 51 to the battery B. lltshould be noticed that relay lil, which io connnou the group of connectors of which connector H is one, is energized by the ringer relay over a, circuit that extends from ground G through springs 1455, common conductor llo and the saidrelay :3l to the battery B. The current flowing inthe middle winding of relay 52 is of sullicicnt strength to operatively energize the saine'ni he springs 14T are adjusted to make before the spring lill breaks away from spring 1&2. so that a new` energizing and locking circuit is established from ground Gl through rings JB and 97, Springs 147 and left han winding of re lay 52 to the battery B. The reloj,r when energized, shifts springs 141 and 148 oui; of Contact with springs 142 and 1&9 and into engagementJ with springs 150 anni 151, respectively, whereby the normals 101 and 102. are extended over conductors 152 und 153 to anv operators position.

It is lo be noted that relay 58, upon finally denergizing, opens the cirruit. of relay 57 which denergizcs lo remore the Short circuit which it placed around high resistance' rela;1 56. vWhen ibis happens relug.' :16 is again included in circuit with ringer Te lay 25, which causes the said relay to decnergize, thereby breaking the circuit of rulny 5l and completing a circuit which ineluded the connector back bridge relay 2l and relay 63 in bringe of conductors 152 und 153. This latter circuit, extends from ground (il hv way of side switrh wiper 46, lower winding of relay 2l? springs 154 and 137 of relay' 25, Sido Switch wiper 49, line wiper 43. normal conductor 102, springs 148 and 151, conductor 153, relay 63, conductor 15:2, springs 15D nd 141, normal conductor 101, hue wiper l2. side Swilch niper 48, springs 13G and 155. and the upper winding of said relay '2l to the battery B. The hack bridge relaja' 21` upon energizing, opens; the contant.; of its springs 79 und illl. B v separaliug springs 79. the short circuit around res ance 156 is removed, thereby including said resistance in a series circuit with release relay 3G to reduce the ('urronl consumption. When springs 10T are seperated the circuit of ringer relay 25 is broken. Relay 56 being included in this circuit also flenergixes a nil opens the circuit of the inferrupter mecha-- nism J. The relay G3. upon energizing'. altracts its armature and lights the signal lamp 6l. The operatonnpon noticing he lamp glowing. throws the answering key K to connect her telephone set across the conductors 152 and 153 `whereby she may ronverse with the calling subscriber and inform him that the substation F is no longer no cessible.`

The callne being notili subscriber at Vsubsination A, by the operator ihn. sab

nation l*1 has been Llisconlimlcfi. hangs up his receiver :unl thereby initiales he reati ration of The :iulolnutic switches. The Separaiiou of the'y swilcnhoolr spring."y by the receiver hook opens the circuit of line relays QG and 2T of the connector H. Three relays` upon decori-glazing, open the circuit of the release relug; 3G. The release relay 36 denergzes to rcmoie ground G25 from the holding winding 13 and to close the following circui of release magnet 6G: Iground G, springs 'FS and lill, springs S1 and 157, release magnet 6G, and oil-normal springs 50 to the battery B. The release magnet energizes lo release lhe connector and the frequency selector S. and its own circuit is broken at vQprings .EO when the switch shaft. reaches-:- normal position. The dencrg'ization of holding winding 13 of the line switch C, permits the :l1-:nature 14 to restore and the plunger arln 1F lo 'ilhdraw the plunger from lhc bank, whereupon all the apparatus associated with the calling line will have been restored lo normal. Upon the release of the connector. ground is removed from conductor 93. whereupon relays 53 and 52 and the cobol? winding of line switch E are denergized, thus resloring all apparatus associated Vwith lha, culled line to normal.

lt has been noted that relays 58 and 59, 582 and 59", 583 and 593, and 58* and 59* are associated. respectively, with ringing gonornors R', Re, ill., and R, which generators correspond fio he four substations on the party line Shown. in Fig. 2. Relays 58 and 59 are adapted fo connect ground G*2 through contacts 138 and '129, contacts 130 and 132, condncor 139. wiper 30. conduror 140, Springs 13% und 136, side switch wiper 48, und line wipei` to normal conductor 161 to initially energize relay in the Ina nner hereinhefore explained. Relays ami 592 are ail-ranged to connect the ungrounfled pole. of the battery [l through springs 1:38, sii-"nga 1539, uml conductor 16D to frequency on zich wiper il? (when on first Contact of the 5ml-ind und thence over ille circuit as vffewiouslly traced. Relays 5R nurl 593 are :munged lo connect ground G through prings 161, snrings 16:?, conductor 163` frequency seleror wiper '25) (when on second roulant of thc third set). conductor 164,V springs: 135 and `13T. siilc switch wipgr 49, nfl line wiper i3 lo normal conductor 102 ior a purpose lo be hereinafter explained. Relays 58* and 59* are arranged to 'connect the ung'roumlcd polo of the battery, B through springs 16?, springs 166. conductor 16T. reqnencin selector wiper 29 (wheuon second Contact of the fourth set), and com rlnctor 1M to normal conductor 102. These rlierenl. Connections are utilized lo control the relay when some partivular station on a pnrtv line discontinued from serijice. When suhstation l? is flifcontinued and it nected to A instead of li'.

is desired that all calls directed to said substation be received by an operator, the terminal B should be connected to terminal C' in the manner shown in Fig. 2. Terminal A will be free. W'hen connected in this manner the relay 52 can only be initially energized by current from the ground side of battery over normal conductor 101 cxplained. If, however, Gr is the substation that is disconnected, the connections should be made as shown in Fig. i1. l/Vhen thus connected relay 552 can be initially energized only by current from the nongrounded pole of the battery over conductor 101 and will therefore be responsive to the relays otE the second group, viz. 582 and 592.

lYhen H is the substation that is discontinued. the connections should be made as shown in Fig. 5. terminal (l being connected to terminal A', and terminals D' and B remainingl disconnected. lWhen thus connected relay 52 can be initially energized only by current from the grounded pole of the battery over normal conductor 102, and is therefore responsive to relays 58 and 59:".

'hen I is the substation that is disconnected, the connections should be made as shown in Fig. (i, wherein terminals D and are connected and terminals C and are left free. lVhen thus connected relay 5;). can be initially energized only by current trom the non-grounded pole of the battery over normal. conductor 102, and is therefore responsive to relays 58'* and 5W.

lf both stations F and G are disconnected the connections shown in Fig. 7 may he used. In this layout terminals D and C' are connected together through resistance. 168 and 169 and then to terminal ll'. A flou' of current from either the grounded or nongrounded terminal of the battery over conductor 101 will initially energize relay 52. 1f stations ll and l are both disconnected thc connections will be as shown in Fig. 7 except the point 17() will be con- If stations F and Il are diseoinu-rted the layout in Fig. 2 may be used with the addition ot a conductor t'rom to Il. It' stations (l and I are disconnected the connections as shown in Fig. 5 may be used with the addition of a conductor from A' to B.

From the foregoing it will be seen that by lsimply making the proper connections between terminals C', D', A and B' the relay equipment is enabled to handle calls for any disconnected substation on the line with which it is associated and switch all such calls to the operators position, thereby providing a very simple and economical method ot' handlingr traffic trunk service.

vhile I have shown and described the principles of my invention in connection with a. party line telephone system of a particular character, various modifications thereof may suggest themselves tov those versed in the art` and l do not, therefore, wish to be limited to the exact construction herein shown and described.

l/Vhat I claim as my invention is:

1. In a telephone system, a line, a plurality ot subscribers` stations on said line, means for selectively signaling' the subscribers on said line, said means comprising a plurality ot' ringing current generators of different character, a group of relays for each generator 'for controlling the application of ringing current to said line, a trunk line leading to a manual switchboard, a battery for operating and talking purposes, means whereby a relay of said group"\connects a terminal of said battery to a conductor of said iirst line` a calling line. another relay, said other relay responsive to said battery connection whereby when the calling line signals for a station on said first line, the servicel of which has been discontinued, the calling line is connected to tln` manual switchboard over said trunk line.

2. In a telephone system, a line, a plurality of subscribers" stations on said line, means for selectively signaling the subscribers on said line` said means comprising a plurality of ringing current generators of different character, a group of relays for each generator for controlling the application ot' ringing current to said line. a trunk line leading to a manual switchboard, a battery for operating and talking purposes, means whereby a relay of said group connects a terminal of said battery to a conductor of said first line, a calling line. another relay, said other relay responsive to said battery connection whereby when the calling line signals for a station on said first line, the service of which has been discontinued. the calling line is connected to the manual switehboanl over said trunk line, and a signal for said trunk line controlled over said connection.

3. 1n a telephone system. a line. a plurality (it-,subscribers stations on said line., means for selectively signaling the subscribers on said line` said means comprising a plurality of ringing current generators of dif-ferent character, a group of relays for each generator for controlling the application of ringing cnrrentto said line, a trunk line leading to a manual switchboarda battery for operating and talking pi-poses, means whereby a relay of said group connects a terminal of said battery toi a con- 'ductor of said first line after said signaling operation, a calling line, another relay. bald other relay responsive to said battery connection whereby when the calling line signals for a station on said first line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

A line leading to a manual switchboard, a.

battery for operatin and talking purposes, means whereby aV re ay of said group con nects a terminal of said battery to a. con doctor of said iii-st line after said signaling operation, a calling line, another relay, said other'rela responsive to said battery connection w ereby when the calling line signals for a station on said first line the servin@ of which han been discontinued, un nnuing line is connected to the manual switchboard over said trunk line, and a signal for said trunk line controlled over said connection.

5.'. In a telephone system, a two-conducto`r line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said 4means comprising a plurality of ringing current neratorg of different character. a battery or operating and talking purposes, groups of relays for said generators for controlling the signaling' over said line, means whereby a relay of each group connects a terminal of said battery to a conductor of said line, a trunk line extending to a manual switchboard, a. calling line, another relay. said other relay connected to a conductor of said first line and responsive to one of said battery connections` whereby when the calling line signals for a station on saidA tirst line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

6. Ina telephone system, atworonductor line, a plurality -of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said meanscomprising a plurality of ringing current generators of different character, a battery for operating and talking purposes, groups o relays for said generators for controlli the signaling over said line, means whereby a relay of cach group connects a. terminal of said battery to a conductor of said line after said signaling operation, a trunk line extending tova manual switchboard, a calling line. another relay. said other relay connected toa conductor of said first line and responsive to one of said battery connections whereby when the calling line signals for aV station on said first line, the service of which has been discontinued. the calling line is connected to the manual switchboard over saidtrunk line.M

7 In a telephone system, a two-conductor line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing current generators of different character, a battery for operating and talking purposes, groups of relays for said generators for controlling the signaling over said line, means whereby a relay of each group connects a terminal of said battery to a condoctor ofsaid line, a trunk line extending to a manual switchboard, a. calling lineanother rclay, said other relay connected to n conductor of said first line and responsive to one of said battery connections whereby when the calling line signals for a station on said first line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line, a signal for said trunk line, and means for operating said signal when said connection is thus extended.

8. In a telephone system, a tivo-conductor line` a pluralitv of subscribers stationsV connected to said line, means for selectively .signaling the subscribers on said line, said means comprising a plurality of ringing current generators of different character, a battery for operating and talking purposes. groups of relays for said generators for controlling the signaling over said linc, means whereby relays in two of said groups connect opposite terminals of said battery to a conductor of said line, a trunk line cxtending to a manual switchboard, a calling line, another relay,Y said other relay connected to a conductor of said first line and responsive to one of said battery connections whereby when the calling line signals for a station on said first line, the service of which has been discontinued,v the calling line is connected to the manual switchboard over said trunk line.

9. In a telephone system, a tivosconducf for line. a plurality of subscribcrs stations connected to said line, moans for selectively signalingthc subscribers on said line, said means comprising a pluralityr of ringing current generators of different character. a battery for operating -and talking purposes, groul'is of relays for said generators for controlling the signaling over said line, means whereby a relay for each of two of said groups connects the same terminal of said battery to different conductors of said line, a trunk line extending to a. manual switchboard, a calling line, another relay, .said other relay connected to a conductor of said first line and responsive to one of .said battery connections whereby when the calling line signals for a station on said first line kthe lservice of which has been discmitiuucd. the calling line is connected to plie manual uitchboard over said trunk ecrans 10. In a telephone system, a two-conductor line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing current generators of dil'erent character, a. battery lor operating and talking purposes, groups of relays for said generators for controlling the` signaling over said line, means whereby a rel'ay for each of two of said groups connects the same terminal of said battery to different conductors of said line after the ,signaling ope' ion, a trunk line extending to a manual switchboard, a calling line, another relay, saidosher relay connected to a conductor of said first line and responsive to one of said battery connections whereby when the calling line signals for a station on said first line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

11. In a telephone system, a two-conductor line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing current generators of different character, a bet-i tery for operating and talking purposes, groups of relays for said generators for controlling the signaling over said line, means whereby a relay of one group and a relay of another group connect the same terminal of said battery to opposite conductors of said line, a trunk line extending to a manual switchboard, a calling line. another relay, said other relay connected to a conductor of said Erst line and responsive to one of said battery connections whereby when the calling line signals for a station on said first line, the service of which has been discontinued, thc calling line is connected to the manual switchboard over said trunk line. 4

l2. In a telephone system, a twoeondue tor line, a plurality of subscribers stations connected toI said line, means for selectively `signaling the subscribers on said line, saidv means comprising a plurality of ringing eurrent generators of different character, a battory for operating and talking purposes, groups of relays for said generators for con- Itrolling the signaling over said line, means whereby a relay of one group and a relay of another Group connect the saine terminal of said battery to opposite conductors of said `line after the signaling operation, a

*trunk line'extending to a manual switchboar-Ll, a calling line. another relay, said other relay connected to a conductor o'l said first line and rcsprmsivc to one of said battory connections whereby when the calling line signals for a station on said lirst line, the servico of which has been discontinued. the callinglinu is connected to the manual switchboard oicr said trunk line.

13. In a telephone system, a two-conductor line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing current generators of different character, battery for operating and talking purposes, groups of relays for said generators for controlling the signaling over said line, means whereby a relay of one group and a relay of 7 another group connect opposite terminals of said battery to the same conductor of said line, a trunk line extending to a manual switchboard, a calling line, another relay, said other relay connected to a conductor of said rst line and responsive to one ot' said battery connections whereby when the calling line signals for a station on said first line, the service of which has been discontinued, the calling line is connected to 8a the manual switchboard over said trunk line. i

14. In a telephone system, a two-conductor line, a. plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing E"aI-rent generators of different character, a battery for operating and talking purposes, groups of relays for said generators for conY trolling the signaling over said line, means whereby a relay of one group and a relay of another group connect opposite terminals of said battery to the same conductor of said line after the signaling operation, a trunk line extending to a manual switchboard, a calling line, another relay, said other relay connected to a conductor of said first line and responsive to one of said battery connections whereby when the calling line signals for a station on said iirst line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

15. In a telephone system, a two-conductor line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing current generators of different character, a battery or operating and talking purposes, groups of relays for said generaors for controlling the signaling over said line, means whereby a relay of each of certain of said groups connects one terminal of said battery to opposite conductors of said line,

yand means whereby a relay of each of cersaid first line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

16. In a telephone system, a two-conductor line, a plurality of subscribers stations connected to said line, means for selectively signaling the subscribers on said line, said means comprising a plurality of ringing current Generators of diii'erent character, a battery ihr operating and talking purposes. groups of relays for said generators for controlling the signaling over said line. means whereby relays of,w certain of said groups connect the opposite terminals of said battery to a conductor of said line, and means whereby relays of each of certain other of said groups connect the op Jo site terminals of said battery to the ot er conductor of said line, a trunk line extend ing to a manual switchboard, a calling line. another relay, said other relay connected to a conductor of said rst line and respon1 sive to one or more of said battery connections whereby when the calling line signals tor a station on said rst line, the service of which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

17. In a telephone system, a two-conductor line, a plurality of stations in bridge of said line, means for signaling a station on said line by projecting ringin current over said two conductors, a relay or controlling the application of said signaling means. a second relay, said second relay connected to one oi said conductors, a trunk line tending to a manual switchboard, a signal for said trunk line, a calling line, a battery for operating and talking purposes, a third relay for connecting a pole of said battery over said conductor to energize said second relay, whereby When the calling line signals for a .station on said rstline. the service oi" which has been discontinued, the calling line is connected to the manual switchboard over said trunk line.

18. ln a telephone system, a line` a pair of talking conductors for said line, a plurality of stations connected thereto, means for signaling a station on said line, said signaling means coniprisingz4 circuit, a relay i'o` *.ntrolliog said circuit, a second relay,

` said second relay connected to one of the talking. conductors of said line, a trunk line extending lo a manual switchboard. a signal for said trunk line. a calling line, a battery for operating and talking purposes, a third relay for connecting a }iolctol said battery over said one conductor to energize said second relay, whereby when thc calling lincsignals for a station on said first line` the service ot' which has been discontinued, thc calling line is: connects-d lo llnmanual sr-.itchboaril over said lrnnh line.

19. In a telephone system. a line, a plurality of stations connected to said line, Said line having a terminal at the exchange, a calling line terminating in the exchange, a generator for signaling a station on said first line, a relay t'or connecting said gen erator with said first line, a battery for operating purposes, a second relay for connect ing one pole of said battery to 'said terminal aiter said iirst relay disconnects said gen crater, a trunk line, extending to an operators position in a manual switchboard, a third relay connected with said terminal when a station on said line is inaccessible to said calling line, the said third relay responsive to' said battery connection to connect said calling line with said operators posi tion over said trunk line a signal for said trunk line, and means for operating said signal when said connection is so extended.

20. In a telephone systenna` line terminating in the exchange or cent-ral oilice, a pair ol' talking conductors i'or said line, a plurality of subscribers stations connected'with said line, a plurality of ringing current gen-- erators of different character, means for applying said generators to said line` to si nal the stations thereon, a trunk line exten ing to a manual switchboard, a signal for sai trunk line, a relay connected t0 the talking conductors of said first line when a station thereon is out of service or disconnected, means whereby calls for the remaining stia tions are received at the respective stations and means including said` relay Whereliy calls for the disconnected station are connected via said trunk line to said manual lswitchboard, and means for `operating said signal. 4

2l. 1n a telephone system, a line terminat ing in the exchange or central oilic-, a plurality of subscribers stations connected with said line, a plurality of ringing current gen cra tors of dill'erent character, means for ap plying said generators to said line to si al the stations thereon, a trunk line exten in to a manual switchboard, a signal for sai trunk line, a relay connected to said irst line when one or more stations thereon arefut of service or disconnected, means W ereby calls for the remaining stations are rec ived at the respective stations and means includ-- ing said relay whereby calls for the disconnected stations are connected via said trunk line to said manual switchboard, and-means for operating said signal.

22. In a telephone system, aline, a pair of talking conductors for said line, a plurality' of stations connected to said line, a terminal for said line in the exchange or central oflice, a ringing current. generator for sigualing one ol' said stations, a calling line, a manual switchboard, a battery for operating purposes. a relay for connecting a pole o1 #aid battcrj, to a talking conductor of said line and means 'responsive to said battery connection whereby when the calling line signals for a station on said first line, the service oi which has been discontinued, the culling line is connected t0 the manual switchboard.

In a telephone system@ line, a pair o talking conductors for said line, a plurality of `stations connected to said line, a terminal for said line in the exchange or central of- Hoe, a ringing current generator for signaling one of said stations, a calling line, a manual switchboard, a battery for operating purposes, e relay for connecting a pole of said battery to a talking conductor of said line and means responsive to said battery connection whereby when the calling line signals for a station on said first line, the Service of which has been discontinued, the calling line is connected to the manual switchboard, ai signal at said switchboard, and ineens for operating said signal.

Signed by nie at Chicago, Cook county, illinois, this 18th day of April, 1916.

VVINFRED T. POWELL. 

